$(document).ready(function() {

	$('textarea[maxlength]').keyup(function(){
		//get the limit from maxlength attribute
		var limit = parseInt($(this).attr('maxlength'));
		//get the current text inside the textarea
		var text = $(this).val();
		//count the number of characters in the text
		var chars = text.length;

		//check if there are more characters then allowed
		if(chars > limit){
			//and if there are use substr to get the text before the limit
			var new_text = text.substr(0, limit);

			//and change the current text with the new text
			$(this).val(new_text);
		}
	});

});